Dual-tone multi-frequency microphone



FIG. 1 is a top, front left isometric view of one embodiment of a dual-tone multi-frequency microphone showing our new design;

FIG. 2 is a front elevational view thereof;

FIG. 3 is a left side elevational view thereof;

FIG. 4 is a right side elevational view thereof;

FIG. 5 is a top plan view thereof;

FIG. 6 is a bottom plan view thereof; and,

FIG. 7 is a rear elevational view thereof.

The broken lines shown in FIGS. 1-4 and 6-7 are included for the purpose of illustrating environmental elements only and form no part of the claimed design. 

The ornamental design for a dual-tone multi-frequency microphone, as shown and described. 